@layered/dns-records/dist/utils.js

Discover publicly available DNS Records for a domain

/**
 * Basic check to test if a string is a valid domain name.
 *
 * @param domain Fully qualified domain name, like example.com or mail.google.com (no protocol or path)
 * @returns Domain in ASCII format
 */
export function validatedDomain(domain) {
    if (domain.endsWith('.')) {
        domain = domain.substring(0, domain.length - 1);
    }
    try {
        const url = new URL(`http://${domain.trim()}`);
        domain = url.hostname;
    }
    catch (error) {
        throw new Error(`"${domain}" is not a valid domain name`);
    }
    const labels = domain.split('.').reverse();
    const labelTest = /^([a-z0-9-_]{1,64}|xn[a-z0-9-]{5,})$/i;
    const tldTest = /^([a-z]{2,64}|xn[a-z0-9-]{5,})$/i;
    const isValidFormat = labels.length > 1 && labels.every((label, index) => {
        return index ? !label.startsWith('-') && !label.endsWith('-') && labelTest.test(label) : tldTest.test(label);
    });
    if (!isValidFormat) {
        throw new Error(`"${domain}" is not a valid domain name`);
    }
    return domain;
}